The invention relates generally to internal combustion engines, and more particularly, to insertion of a cylinder liner or sleeve into a cylindrical bore of a one-piece integral cylinder block and cylinder head member, and boring and honing of the cylinder liner or sleeve. In the past, cylinder liners were commonly bored and honed after full insertion thereof into the cylindrical bore of a cylinder block. When a separate cylinder head was employed, such full insertion and subsequent boring and honing did not involve problems of chip breaking and chip disposal and disposal of honing debris. However, full insertion of a cylinder liner into the cylindrical bore of a one-piece cylinder block and cylinder head member and subsequent boring and honing involves breaking the chip at the inner end of the liner, without the availability of a chip clearance area and with possible consequent engagement of the boring tool with the adjacent cylinder head surface. In addition, full liner insertion also prevents running off or run-by of the inner end of the honing tool or stone from the inner end of the cylindrical surface of the cylinder liner. In the absence of such running off, i.e., movement of the inner end of the honing tool or stone beyond the inner end of the inner cylindrical surface of the liner, the inner end of the honing tool or stone is exposed to excessive wear.
One possible solution to the problem of boring and honing the liner of a one-piece cylinder block and cylinder head member after full insertion of the liner into the cylindrical bore involves the employment of an under-cut or counter bore at the inner end of the inner cylindrical surface of the liner. Such a counter bore or area of increased diametric volume at the inner end of the liner or sleeve is minimal and highly undesirable Because this area can be wiped by the piston or piston rings and, depending on the axial length thereof, is diametrically too large. Furthermore, the increased volume provided by such an under-cut or counter bore can trap fuel and lubricant which aggravates emissions.
Another possible solution involves boring and honing of the liner or sleeve prior to insertion of the liner or sleeve into the cylinder block. However, with such pre-boring and honing, followed by insertion, problems arise with respect to proper location of the axis of the inner cylindrical surface, with respect to proper lateral bore spacing in multiple cylinder engines, and with respect to deformation of the cylindricity of the inner cylindrical surface consequent to the insertion.
Attention is directed to the following U.S. patents:
______________________________________ U.S. Pat. No. Inventor(s) Issue Date ______________________________________ 1,927,594 C. A. Olson September 19, 1933 3,273,423 D. B. Rottler September 20, 1966 3,905,717 Daryl G. Brooks September 16, 1975 4,307,636 Patrick J. Lacey December 29, 1981 4,557,640 D. B. Rottler December 10, 1985 4,701,081 Hashimoto, et al. October 20, 1987 4,847,961 Donovan, et al. July 18, 1989 ______________________________________
Attention is also directed to Japanese application 3-206473 filed Jul. 23, 1991.